ORANGE PARK, Fla. -- The mother of a 7-year-old Florida girl whose body was found in a landfill made a promise on television Friday morning to the unknown killer: "We'll get you."

One day after investigators positively identified a body found in a Charlton County landfill as that of 7-year-old Somer Thompson, her mother, Diena, appeared red-eyed on all three network television morning shows, then sat down for an interview with Channel 4's Casey Black.

Somer vanished on her one-mile walk home from school Monday in a heavily populated residential area in the Jacksonville suburb of Orange Park. Searchers combed the area before investigators, following garbage trucks that collected trash Tuesday, spotted her lifeless legs in the Chesser Island Landfill just north of the Florida-Georgia border.

An autopsy to establish the cause of death was completed, but authorities would not disclose their findings. At a news conference, Clay County Sheriff Rick Beseler would not say if Somer had been sexually assaulted or answer other questions about the condition of the body, but did call her death "a heinous crime."

Friday evening, Diena appeared at a candlelight vigil held for Somer, saying her daughter's body will be released to the family for the viewing and memorial next week, but she will not be able to see the body at the request of police.

Diena said a lock of Somer's hair will be given to her.

Florida Department of Law Enforcement crime scene technicians spent Thursday afternoon and evening into Friday processing a vacant, burned-out home on Gano Avenue, about 500 yards from Grove Park Elementary School and not far from where Somer ran off from her twin brother and older sister about 2:45 p.m. on Monday. The last time Somer was seen was on the sidewalk in front of that home.

Friday morning, spokeswoman Mary Justino said that work would continue through the day and the FDLE has made processing evidence in the Somer homicide investigation "their No. 1 priority."

Justino said Friday afternoon that about 900 leads have now come into the Clay County Sheriff's Office tip line, and about 200 of them remain under investigation. At least 50 detectives are working full-time on the criminal investigation -- some still looking for evidence in the 225 tons of garbage that arrived at the Georgia landfill on Tuesday, and the rest working leads in Orange Park.

"We certainly remain encouraged at the progress we are making in this case, but we do want to still encourage people who think that they may have information that could help us to call in to that tipline (1-877-227-6911)," Justino said.

Justino said detectives had completed the questioning all registered sex offenders who live within a 5-mile radius of where Somer disappeared.

"All 90 have been contacted in person, their homes have been searched, their properties have been searched, their families have been spoken to and we feel certain at this time that we do not have any suspect that are members of that group," Justino said Friday morning.

The Justice Coalition reward fund for the arrest and conviction of the person or persons responsible for the killing of Somer Thompson is $26,000. Crimestoppers has an additional $5,000 reward for an arrest, bringing the total reward to $31,000.

Diena Thompson said she does not know any details of the investigation. She said she hopes the killer gets the death penalty.

"Every morning when I get up, I just get up thinking it's just all a bad dream, and you come out and you see everything that everybody's brought and you know it's real," Thompson said.

Missing child posters featuring Somer's face, with chubby cheeks and thick brown bangs, still plaster nearly every utility pole along the mile-long route from her elementary school to her home.

Investigators on Thursday searched a vacant home a couple of blocks into Somer's daily route, just past a wooded area and across the street from a playground and baseball diamonds.

"It's crazy to think something like this could happen here," said neighbor Andrew Carlson, 17, as he watched officers in protective white suits go in and out of the empty house and comb through a construction trash bin outside. Construction crews had been working on the house, which was damaged in a fire several months ago, he said.

Authorities said Somer squabbled with another child Monday and then ran ahead of the group of kids and was never seen again.

At an intersection about halfway into her walk, where Somer would have crossed the street and turned right on the road that led straight home, a purple ribbon -- which supporters and family members have been wearing -- was tied to the pole of a stop sign.

On Thursday evening, a steady flow of people -- many of them parents, clutching the hands of young children -- walked down that same road toward Somer's house to support her grieving family with a candlelight vigil.

Around a tree across the street from the girl's house, supporters had created a memorial, leaving hundreds of stuffed animals, flickering candles, signs and balloons.

Diena Thompson came out with purple ribbons tied in her hair to thank the group who sang "Amazing Grace" and "You Are My Sunshine," then recited the Lord's Prayer.

"I wish I could hug every one of you," Thompson said. "I love every one of you."

Cries of support came from the crowd of about 200: "The community is behind you!" and "We're here for you. You're in our prayers."

Somer's father, Sam Thompson, talked to a North Carolina TV station Thursday about his daughter's death.

"I'm so angry I can't express with words," Thompson said. "They disregarded my child like a piece of trash. I hope they crucify him. I forgive them for what they've done because the Lord says I have to, but as far as what I'm feeling, it's pure anger. I'm trying to get over that. There's some really sick people in this world."

The sheriff said the quick discovery of Somer's body, two days after she disappeared, may have saved precious evidence that could lead to her killer.

"Had we not done this tactic, I believe that body would have been buried beneath hundreds of tons of debris, probably would have gone undiscovered forever," Beseler said.

Investigators will presumably try to pinpoint the trash bin or garbage can where she was dumped, based on the trash around her and the truck's pickup route.

"I fear for our community until we bring this person in," Beseler said Thursday. "And we're going to work as hard as we can to make this community safe."